Method of and means for operating dynamo-electric machines.



B. G. LAMME.

METHOD OF AND MEANS FOR OPERATING DYNAMO ELEGTRIG MACHINES. APPLIUATIONFILED AUG. 2, 1906.

925,355. Y Patented June 15, 1909.

3 BHEETS-8HEBT 1.

Big 7.

ATTdRNEY B. G. LAMME. METHOD OF AND MEANS FOR OPERATING DYNAMO ELECTRICMACHINES.

' APPLICATION FILED .umz, 1906.

3 SKEETS-BHBBT 2.

925,355. Patented June 15, 198?,

B. G. LAMMB. METHOD OF AND MEANS FOR OPERATING DYNAMO ELECTRIC MACHINES.

APPLICATION FILED AUG.2, 1906.

Patented June 15, 1909.

3 SHEETS-SHEET 3.

: LLLC.

WITNESSES.

@m s. MW?

a rmen earns BENJAMIN G. LAMME, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO'WESTINGEO'USE ELECTRIC dz MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

OF AND MEANS FOR OPERATING D'EZ'NAIKO-EL GIIELIC.MAGHEI no. access.

Specification of Letters l ment.

?atent ed Application fil ed August 2, 1908. Serial No. saasse.

To all whom it may concern:

Be it-lrnown that I, BENJAMIN G. LAMME, a citizen of the United States,and a resident of Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Methods ofand Means for Operating Dynamo-Electric Machines, of which the followingis a specification.

My invention relates to methods of operating dynamo-electric machineseither as motors or as generators, and to means for v practicing suchmethods.

The object of my invention is to provide a method of, and means for,operating alternating current motors of the commutator type, that areemployed to pro 01 vehicles and the like, whereby they may be caused toact as braking generators.

In the operation of electric railway vehicles the propelling motors arefrequently employed as braking generators, but since the field magnetand armature windings thereof are usually connected in series relation,they have not heretofore operated as generators under stable conditions.In order to obtain stable or controllable conditions of operation, thefield magnet strengths must remain invariable or be subject to variationby an operator, as is the case when the field magnet whirling isseparately excited. Separate excitation of the field magnet winding of adiroot current motor is impracticable,- because of the extremely largeresistances necessary to reduce the voltage otthe sup )ly circuit tothat suitable for application to t e field magnet winding. Whenalternating current motorsot the commutator type of construction areemployed to propel a vehicle, however, and the voltages applied theretoare varied by altering the active length of a transformer winding incircuit therewith, I propose to separately excite the field magnetwindings of the motors, when operating as generators, by connecting themdirectly to the transformer winding, and to vary the field magnetstrengths by altering the points or connection. of the field magnetwindings with the transformer winding. In the present instance, thearmatures are connected in a circuit including either a brakingresistance or the winding of a mechanical brake. in another application,Serial No. 401,325, WillGll'lS a division of the present application,one oi the propelling motors is utilized comprises a trolley conductor 3and as an excitcr for the field magnet windings oi the remaining motors,the field in x winding of the e-Xciter and the armatures or theremaining motors being connected to distributin circuit, and in stillanother plication, Serial No. 401,324, which is division of thisapplication, the field 111 gust and armature windings of the motorremain connected in series for generator operation, but the armature ofa separate commu ator generator is connected in shunt to the fieldmagnet winding, the field n .agnet winding the generator being connectedto the distributing circuit. I

Figure 1, of the accompanying drawings, is a diagrammatic view of asystem oi distribution that embodies my invention, and Figs. 2 and 3 aresimilar views of modifier;- tions of the system of Fig. 1.

A Winding 1 of an anto-transformer 2 may be supplied with alternatingcurrent from any suitable sup ly circuit such as that which raclc rail4, and the connections thereto, and the circuit arrangements of fieldmagnet winding 80 5 and armature 6 of a motor oi the Cl')il3llli.l tatortype may be adjusted by means of a controller 7 that is adapted tooccupy the one or the other of the positions irnlicatedby broken ordotted lines G and M. The circuit .3

arrangements corresponding to ca oi inc positions are indicateddiagramma ici ll at the lower extremities oi the broken lines. When thecontroller occupies the position. indicated by the line M, the fieldmagnet and armature windings oi the motor are ii-- ncctcd in seriesrelation, as is usual when mo tors are employed for the propulsion. olvchiclos, spocd variation being cll'cclcd l adjustment oi' the voltageapplied to the molar by means of an auxiliary controller if it isdesirable to employ the motor as u b generator, as, for instaz u'c, whensic-pp vehicle or when a vehicle is dcscendi grade, the mntrollcr may becaused cupy the position indicated by the lure whcrcupmi the iicldmagnet winding 5 la. comes connected to the transformer Xll and thearmature (i to a suitable brain sistanco 9, as indicated by the diagramlower extremity of the line G. The dc amount oi braking aii'orded by thein when operating thus as a generator, z adjusted by varying the amountof re 9 included in sari .n' with the ar ture o, o,-.

by varying the field strength. Variation of the field strength may beaccomplished by adjusting the voltage applied 1 to the field magnetwinding 5, as, for instance, by means of the controller 8, or, ifdesired, it may be effected by means of a rheostat or by a va riablechoke coil, the former means being preferred because the waste of cner yincident to its use is practically negligib e.

It may be found in practice that, with the arrangement of Fig. 1, thevoltage gradations desirable for effecting speed variation of the motorwill be unsuitable for effecting variation of the field strength, andfor that reason an auxiliary transformer 10 (Fig. 2) of substantiallythe same voltage as that of the mo- 'tor may be connected between anauxiliary controller 11 and the grounded terminal of the maintransformer winding 1, when the motor is operated as a generator, andfield magnet winding 12 may be connected between suitable pointsthereof, armature 13 being connected as before to a braking resistance14. The circuit arrangements are shown diagrammatically at the lowerextremity of the line G of Fig. 2 and are brought about when thecontroller occupies the position indicated by 'that line. The voltage aplied to the field magnet winding may then lie adjusted by means of thecontroller 11, and if desired, also by altering the points of connectionof the field magnet winding with the auxiliary transformer winding 10.

The invention may also be employed as indicated in Figs. 1 and 2 withmore than one motor, in which case braking may be efiected gradually, ifdesired, by connecting armatures 17 and 18 of the motors in successionto the braking resistance substantially as indicated in Fig. 3, in whichthe controller 7 is adapted to occupy two positions that are indicatedrespectively by the lines G and G. When the controller occupies positionG only the armature 18 is connected to braking re sistance 19, and whenit occupies the position G the armature 17 is also connected to thebraking resistance.

It will, of course, be understood that the devices 9, 14 and 19 may alsorepresent the operating or controlling windings of mechanically appliedbrakes of any of the suitable well known forms.

Not only are there advantageous results incident to the use of agenerator of the commutator type as above set forth for exciting thefield magnet winding of another dynamoelectric machine when operating asa generator, but if the field magnet winding is similarly excited whenthe machine is operating as a motor, the inductive load upon thedistrlbutlng circuit may be considerably less than when the said windingis supplied di rectly from the distributing circuit. While the powerfactor of the currentsupplied from the distributing circuit to the fieldma net winding of the exciter generator is very ow, it may be arranged,as for instance by operating the exciter at a comparatively high speed,so that the amount of current may be small as compared with thatrequired of the armature for exciting the field magnet Winding of themotor, which is also of avery low power factor. Thus the total Inductiveoad upon the distributing circuit may be less than when no auxiliarygenerator is em ployed. It will, of course, be understood that theseries characteristic of the motor is not retained in this arrangement,and that it will tend to run at a constant speed. However, speedvariation may be readily effected by adjusting the field strength of themotor.

I claim as my invention:

1. The combination with a distributing circuit, a dynamo-electricmachine, and a resistance, of means for connecting the field magnet andarmature windings of the machine to the circuit and in series relationfor operation thereof as a motor, and for connecting the field magnetwinding to the circuit, and only the armature winding in closed circuitwith the resistance, for operationof the machine as a generator.

2. The combination with a distributin circuit, a motor havingseries-connected field magnet and armature windings, and a resistance,of means for connectin the field magnet winding of the motor to t ecircuit, and only the armature winding in closed circuit with theresistance, for operating the motor as a generator.

3. The combination with a distributing circuit, a plurality of motorshaving seriesconnected field magnet and armature windings and aresistance, of means for connecting the field magnet windings of themotors to the circuit, and only the armature windings in succession tothe resistance, for operation of the motors as generators.

4. The combination with a distributing circuit, a motor havingseries-connects field magnet and armature windings and a resistance, ofmeans for connecting the field magnet winding of the motor to thecircuit, and only the armature winding in closed circuit with theresistance, and means for varying the field magnet strength, whenoperating the motor as a generator.

5. The method of operating as a generator a motor havingseries-connepted field magnet and armature windings which consists insupplying the field magnet winding from the circuit from which the motoris supplied and in connecting only the armature in closed circuit with aresistance.

6. The method of operating as a generator a motor havingseries-connected field magnet and armature windings which consists insupplying the field magnet winding from the circuit from which the motoris supplied, in connecting the armature to it resistance, and in varyingthe field magnet stren 7. The method of operating a plurafity of motorsas braking generators Whlch consists in causing them to becomegenerators in sue-- cession S. The combi dynamo-electric brakingcircuit.

9. The metho nation with a plurality of machines that may be operd ofoperating as generators a plurality of motors having series-cs2, fieldmagnet and armature "y in conslsts 1n supplying the irelri n ings of themachinesfrom the circrnt phes the motors and connecting the tures insuccession to s resistance.

e hereunto sy oi Juiy,

In testimony whereof, 4 subscribed my name this Zoe-n. 1906.

